The identification of interacting male-female reproductive proteins is imperative for a molecular understanding of fertilization. Generally, the molecular descriptions have relied upon studies of male reproductive proteins. This research proposal is aimed at characterizing interacting male- female reproductive proteins in abalone, a system with for which many of the molecular details of fertilization are well established and one that serves as a model for the study of reproductive molecules and evolution of species-specific fertilization. Three specific aims relating to abalone are proposed: Aim 1. Biochemical analysis of interactions among gamete recognition proteins. Aim 2. Molecular description of VE supramolecular structure through analysis of ZP glycoprotein interactions. Aim 3. Abalone sperm proteome and functional analysis of a newly discovered novel gamete recognition protein. The research proposed is innovative in that it is highly integrative, utilizing genomic, proteomic, biochemical, and computational methods. This work will test for evidence of direct functional interactions between sperm and egg molecules. The functional specificity sperm-egg interaction will be further investigated. Together these research aims represent a significant advancement in our understanding of the molecular interactions between sperm and egg, the evolutionary dynamics of genes encoding sperm/egg proteins, and will contribute to a broader understanding of the function and evolution of reproductive genes.